The role of prostaglandins in hypertension is under study. Measurements of prostaglandins A, E, F are being made in plasma and renal tissue of animals and man. The effect of sodium, hypertension, pregnancy, and angiotensin infusions on these levels are under study. Infusions of antiprostaglandin antibody and indomethacin on the blood pressure of rats with experimental hypertension is under investigation. The effect of angiotensin II and indomethacin infustions on prostaglandin release and utero-placental blood flow is being studied in pregnant monkeys.